Lumber trimmer



Nov. 4, 1930. s. K. PRESCOTT ,780,362

LUMBER TRIMMER Filed Oct. 28, 1929 3 Sheets-Sheet l Nov. 4, 1930. s. K. PRESCOTT LUMBER TRIMMER Filed Oct. 28, 1929 3 Sheets-Sheet 2 od? y? 30 Nov. 4, 1930. s. K. PRESCOTT LUMBER TRIMMER Filed Oct. 28, 1929 3 Sheets-Sheet 3 Patented Nov. 4, 1930 UNITED STATES PATENT OFFICE SUMNER K. PRESCOTT, 0F SEATTLE, WASHINGTON, ASSIGNOR TO PRESCOTT IRON WORKS, 0F SEATTLE, WASHINGTON, A CORPORATION OF WASHINGTON LUMBER TRIMMER Application filed October 28, 1929. Serial No. 402,889.

This invention relates generally to improvements in lumber trimmers and more particularly to ii'nprovements in automatic lift mechanism for lumber trimmers of the type forming the subject matter of Patent 1,522,940, granted January 13, 1925, to J. L.

Breeze for lumber trim saw.

One of the principal objects of the present invention is to provide a double mechanical 10 lift unit for lumber trimmers which simplifies and compacts the construction and which permits the use of a Variable spacing of the trimmer saws as, for example, a one or two foot spacing of the saws.

Another object of the invention is to provide a device of this character which is simple and durable in construction, reliable and effective in operation and easy and inexpensive to manufacture and install.

Other objects and advantages reside in certain novel features of the construction, ar rangement and combination of parts which will be hereinafter more fully described and particularly pointed out in the appended claims, reference being had to the accompanying drawings forming a part of this specification, and in which:

Figure 1 is a plan view of a double lift unit embodying the present invention;

Figure 2 is a view thereof in end elevation;

Figure 3 is a View thereof in rear elevation, that is, looking toward the left in Figure 1:

Figure 4 is a view in longitudinal vertical section taken approximately on line 44 of Figure 1, and with parts shown in elevation for the sake of simplicity in illustration;

Figure 5 is a detail view in elevation of the supporting bracket employed for each lift unit and of one of the cam tracks or flanges carried thereby for controlling the operation of the lifting pawl;

Figure 6 is a fragmentary view partly in side elevation and partly in vertical section showing how the lift unit is connected up with the saw frame;

Figure 7 is a fragmentary view partly diai-fgrammatic and partly in elevation showing how the lifting yokes n ray be positioned to obtain a two foot spacing of the saws;

F lgure 8 1s a similar View showing how the lifting yokes are adjusted to obtain a one foot or minimum soacin of the saws:

Figure 9 is a detail perspective view of the shiftable section of one of the cam tracks or guides employed for and Figures 10 and 11 the raising pawls;

are detail views in top plan of a lowering and lifting pawl, respectively.

Referring now to Fig that the usual trimmer ure 6, it will be seen table designated at 1 is provided and has an upwardly inclined top 2 over which the upper run of a conveyor designated generally at 3 travels, the

conveyor advancing the ming saws 1n the usual the table is a saw supporting lumber to the trimmanner. Ad acent frame work 4:

ported and has a saw tatable therewith. The tated in the usual manne the manner shown in the referred to.

7 fixed thereto and roarbor 6 may be ror, as, for ance, in Breeze patent above As illustrated diagrammatically in Figures 7 and 8, the saws of a double lift unit des 10. Although a single of each saws are raised and lowered pair of adjacent under the control ignated generally at unit 10 serves two saws, each saw may be independently raised and lowered.

Referring now to Figures 1 to 4, inclusive, the numeral 11 designates the line shaft or other power actuated.

double lift unit has a ported upon and bolted and carrying a section drive shaft. Each base plate 12, supto suitable framing, al housing 13 provided with a bearing 14 in whichthe adiacent portion of the line shaft 11 is rotatably supported. Within the housing 13, a pinion 15 is keyed to the line shaft and meshes with a gear wheel 16 keyed to the central portion of a counter shaft 17 18 formed on the housin sides of the gear 16.

j ournaled in bearings g 13 on the opposite ith this construction the shaft 17 of each double lift unit is constantly turning whenever the line shaft is driven.

At each end of the shaft 17, an arm 20 is provided, each arm 20 having a hub 21 provided with a bushing 22 and rotatably fitted on its end of the shaft 17. A washer 23 and pin 24 prevent endwise displacement of each arm 20 off of its end of the shaft 17. The outer end of each arm 20 is provided with a head 25 having an axial opening 26 receiving a rank pin 27, the pin 27 being held or secured in the opening 26 by means of a set screw 28. The outer end of each pin 27 projects outwardly beyond its arm 20 and extends through a roller bearing assembly 29 fitted in an opening provided therefor in the upper end of a link 30. A lubricating fitting 31 is provided for the bearing 20. The link is held on the pin 27 and the bearing assembly 29 is retained in place by means of a washer 32 and pin 33. The lower end of each link is provided with a lateral extending extremity or end portion 34 (see Figure 4) apertured to receive the upper end of a rod 35. Nuts 36 secure the rod to the link 30 in various adjustments. Referring now to Figures 6, 7 and 8 it will be seen that the lower end portion of each rod 35 extends through the apertured body portion 37 of a lifting yoke 38. a head 39 at the lower end of each rod engaging the body portion 37 of each lifting yoke to limit the relative upward movement of each rod 35 relative to its lifting yoke. Each lifting yoke 38 also includes a pair of diverging arms 40 integral with one side of its body portion 37 and offset from the body portion 37 as illustrated in Figures 7 and 8. The lower ends of the arms 4-0 are apertured to receive a pivot 41 (see Figure 6) which connects the lifting yokes to pivot lugs 42 integral with the saw frames 5. With this construction the offset arms 40 of the lifting yokes may be swung to a position shown in Figure 7 to provide the maximum spacing between the saws or they may he swung to the position shown in Figure 8 to provide minimum spacing be tween the saws. This operation of the lifting yokes together with the construction of the lifting units permits of either a one or two foot saw spacing. lVith separate lifting units this is not permissible. as separate lifting units must be so spaced as to preclude a one foot spacing of the saws.

Returning now to the double lifting unit it will be seen that means is provided for selectively clutching or connecting either arm 20 to the shaft 17 for the purpose of either controlling the lowering movement of the arm and consequently of the associated saw frame or for the purpose of imparting a lifting movement to the arm and to its connected saw frame. In carrying out these purposes a toothed wheel 45 is provided on the shaft 17 adjacent each end thereof. The teeth of each wheel are designated at 45 and as shown in the drawings are uniform and are regularly spaced about the periphery of the wheel, each tooth having its opposed transverse or lateral faces substantially straight. whereby one transverse face of each tooth is adapted to coact with a lowering pawl, and the opposite transverse face of each tooth is adapted to coact with a lifting pawl. Each toothed wheel 45 has an inwardly offset hub 46 positioned on the shaft just inwardly of the hub of the adjacent arm 20 and keyed as at 47 to the shaft 17 (see Figure 4) The head 25 of each arm 20 overlies its a ciated toothed wheel 45 and enlarged in a direw tion c rcumferentially thereof. The extremities of each enlarged head 25 are bifurcated and receive and pivotally support a pawl 49 cooperable with the toothed wheel 15 to control lowering of the arm 20 and saw frame I; and also a pawl 50 cooperable with the toothed wheel 45 to impart lifting movement to the arm 20 and to the saw frame 5 conilPCtQtl thereto.

The lowering pawls at the two ends of the unit are of similar construction though of opposite hand. shown in Figure 1 u d 3. The lowering pawl 49 has a tail Til WlllL coacts with a substantially HEIUhGRHHlSIZ track to control its engagement with the toothed wheel that to hold the pawl out of gcment with the too hed wheel din-i i the raisu movement of the arm 30 and in the upper inactive or stopped pesition of the arm 20. wherein the arm 20 is just past upper dead center, as shown in Figure 2. Timing the ow ring movement of each arm 20. the tail 51 of its pawl 49 leaves trael;

that the pawl 49 engaged w unde nice of its h carried id 58 provided the s button or heaii looped or night portion itu its pawl at?) to tend to ur e i wheel 45. town in the drawings nd secured to siou 5a each rack 52 has outward -item t a bracket 56 and its upper end to an a ular lug 57 bolted at 58 to ti same bracket 56. One bracket 56 18 shown in detail in Figure 5 and each bracket 56 is bolted as at 57 to lugs or attachment fixtures 539 formed integral with the base plate 12 (corm pare l igures 1, 2 and 'Each lifting pawl 50 is provided with a ly extending lug 6O cooperahle with a track-way 61, the major portion of which is formed integral with and projects outwardly from the bracket 56, but a shiftable section -3 of which, is slidably supported on the brac at 56 so that it may be alined with the major portion of the track 61 or Withdrawn inwardly from the plane of such major arm 20 and the saw frame.

portion for a purpose which will hereinafter more clearly appear. During the lowering movement of any arm 20 and of the saw frame connected thereto, its lifting pawl 50 is held away from the toothed wheel by virtue of the engagement of its lug 60 of the pawl with the associated track 61. lVhen the downwardly moving saw frame has reached its lowermost position the associated lug 60 is still engaged with the shiftable section 62 of its cam track 61. The saw frame and arm 20 remain in this lowermost position under the influence of gravity.

It is to be noted that the lowering pawl 49 is not effective to impart lifting movement to the arm 20 or saw frame. and in the lowermost position of the arm 26, the teeth of the wheel 45 would only click idly past the lowering pawl 49 if the latter were left engaged with the wheel. To eliminate this clicking, however. each pawl 46 is retracted in the lowermost position of the arm 20 since at such time its tail engages the lower end of the track 52 to move the pawl 51 away from the toothed wheel notwithstanding the action of its spring.

To permit the lifting pawl 50 of the lowered arm 20 to engage the toothed wheel and operate to elevate its arm 26 and the saw frame connected thereto, the shiftable cam track section 62 of the unit is pulled inwardly and disengaged from the log 60 of the pawl 50 thereby permitting the pawl 56 to engage the toothed wheel 45 and effect elevation of the The engagement of this pawl 50 with the toothed wheel 45 continues until the arm 26 has just z-i'lightly passed beyond the upper dead center position when the lug 60 rides onto the upper end of the fixed section 61 of the cam tract: to disengage the pawl 50 from the toothed wheel. At this time the rearward end of the pin 27 which projects inwardly beyond the head the arm en gages a stop bolt to bring t e lifting li'l0(l1 aoism to rest. Each bolt 70 is slidably fitted in a guide-way 71 provided therefor on the bracket 56 and is inter-i .neeted with the shiftable track section 62 o 1' its unit by means 0 i a lever 72 fulcronied as at 72 on the bracket 56 and having its ends appropriately connected with the bolt and with the slidable mounting member 62' of the shiftable track section. By virtue of this interconnection, when either bolt 70 retracted the track section 62 interconnected thereto projected into operative position. that is; into a position in which it will hold the lifting pawl retracted or inactive whereas when the bolt 1'0 is projected to operative position in which it effective to stop the arm 20 in elevated position, the associated track section 62 is retracted to permit the l fting pawl f-( of the on to engage the toothed wheel and elevate the arm 20 and the saw frame.

Each bolt 70 has a pair of upstanding lugs 75 for receiving between them an arm 76 of a control lever designated generally at 77. The arm 76 of the control lever 77 has a downwardly extending pin 78 fitted in a bearing opening provided therefor on the bracket 56 and providing the support for the lever. Adjacent the pin 78 the arm 76 has a serrated hub 79 surrounding an upstanding threaded stud 80 integral with the arm 76 and adapted to be interfitted with an apertured and serrated hub 81 formed on a second lever arm (compare Figures 2 and The serra tions of the hubs and two arms are inter fitted in various adjustments and are held in engagement by a nut 83 threaded on the stud 80 and bearing against the hub 81. The arms 84- are offsetfrom each other so that they may overlie with one another in the assembly without interference, as shown in Figure 3. The control lines are connected to the arms 84. Preferably, the bolts 70 are urged or biased to a projected position by means of coil springs 85 connected to the arm 76 of the levers and to anchoring lugs 86 on any suitable stationary part.

When any saw frame is elevated its arm 20 is in a position slightly beyond the upper dead center as shown in Figure 2 in which position the weight of the parts tends to lower the arm 20 and consequently to hold the rearward end of its pin 27 engaged with the associated stop bolt 70 which is projected at this time. If it is desired to lower any one of the elevated saw frames the appropriate control line is manipulated to retract the bolt 70 of the controlling unitof the selected saw frame. This simultaneously projects the shiftable cam track section 62 of the unit. As soon as the bolt 70 is withdrawn the weight of the parts starts the arm 20 to move in a clockwise direction as viewed in Figure 2. At the start of this movement, the tail of the lower pawl 49 rides off of the cam track 52 so that the lowering pawl snaps into en gagement with the toothed wheel 45 to control the lowering of the saw frame. When the saw frame has been completely lowered the parts remain in lowermost position under the action of gravity since the shiftable cam track section 62 is projected at this time to hold the lifting pawl 50 disengaged from the toothed wheel. WV hen the control line is again manipulated to cause or permit the bolt 70 to be projected, then the shiftable cam track section 62 is withdrawn from engagement with the lag of the pawl 50 and the pawl 50 snaps into engagenient with the toothed wheel and eii'ects lifting of the saw frame. The lifting movement is automat ically stopped when the arm 20 reaches the position shown in Figure 2, due to the automatic disengagement of the pawl 50 from the wheel 45 and to the engz. ment of the rearward end of the pin 27 w ith the stop bolt 70.

With the construction above described, two

lifting units are served by the same counter shaft and a single gear and pinion. Further, the number of bearings required for two lifting units is materially reduced and the construction is rendered so compact as to permit of the provision of shiftable lifting yokes such as e0 whereby the saw spacing may be varied and the saws may be brought very close together.

The. invention claimed is:

1. in a lumber trimmer having the usual saw frames, a double lift unit including a single counte' shaft, tn 0 liftin arms, one at each. end of the counter shaft, means cooperable with an intermediate portion of the count e shaft to rotate the same, mean: for controlling the connection of each lifting arm with the counter shaft, and connections between each lifting arm and a saw frame.

ln a lumber trimmer having the usual saw frames, a double lift unit including a single counter shaft, two lifting arms. one at each end of the counter shaft, Incans cooperable with an intermediate portion of the counter shaft to rotate the same, "leans for controlling the connection of each lifting arm Vith the counter shaft, and connections between each lifting arm and a saw frame, each of said connections inchuling a shiftable lifting yoke, said lifting yokes providing for variable spacing of the saws.

In a lumber trimmer having the usual saw frames, a double lift unit including a single counter shaft, two lifting arms, one at each end of the counter shaft, means cooperable with an intermediate portion of the counter shaft to rotate the same, means for controlling the connection of each lifting arm with the counter shaft, and connections between each lifting arn'i and a saw frame, each of said connections including a shiftable lifting yoke having offset arms positionable to vary the spacing of the t. In a lumber trimmer having the usual Raw frames, a. double lift unit inclmling a constantly driven shaft. two lifting; arms loosely mounted thereon, a toothed wheel fixed to the shaft adjacent each lifting arm, a lifting and a lowering pawl mounted on each arm and cooperable with the a sociated wheels, means controlling the ac ion of said pawls and a connection between each arm and a saw frame.

In a lumber trimmer having the usual saw frames, a double lift unit including a contantly driven shaft, two lifting art loosely mounted thereon, a toothed w l fixed to the shaft adjacent each lifting: arm, a lifting and a lowering awl mounted on each arm and cooperablc with the associatec wheels, means controlling the action of said pawls and a connection between each arm and a saw frame, each of said connections including a shiftable lifting yoke positionable to vary the spacing of the saw frames.

6. In a lumber trimmer having the usual saw frames, a double lift unit including a constantly driven shaft, two lifting arms loosely mounted thereon, means for selectively clutching either arm to the shaft to control the lowering thereof or to impart lifting movement thereto, and a connection between each arm and a saw frame.

7. In a lumber trinnner having the usual saw frames, a double lift unit including a constantly driven shaft. two lifting arms loosely mounted thereon. means for selectively clutching either arm to the shaft to control the lowering; thereof or to impart ii ting movement thereto. and a connection between each arm and a saw frame. each of said connections inclmlinna shifta lc lifting yoke positionable to vary the spacxngi of the saw frames.

8. In a lumber trimmer having); the usual saw fames. a mechanical lift unit for imparting raising and lowering movement to a saw frame, and a connection between said lift unit and a. saw frame and comprising a lift rod. a lifting yoke rotatably connected to said lift rod and having an offset arm.v and releasable means for securing said arm to the saw frame in either of the positions to which it is shiftable.

In witness whereof, I hereto illilfi nature.

SUMNER K. PRESCOTT. 

